1. Field of the Invention
The present invention relates to a rotary electric shaver that rotates an inner cutter while making sliding contact with a substantially disk-shaped outer cutter, thus cutting hair (whiskers, etc.) that enters slits in the outer cutter by the rotating inner cutter.
2. Description of the Related Art
In electric rotary shavers having a single or a plurality outer cutters, it is well known that the shaving feeling improves if the outer cutter(s) is designed to be movable upward and downward (or to be floatable) in an axial direction thereof. In addition, by way of designing the outer cutter to not only be movable upward and downward but also be tiltable in an arbitrary direction so that the outer cutter tilts to follow the curvature of the shaving surface, the closeness between the outer cutter and the shaving surface increases, and the shaving feeling improves even more.
Japanese Patent Application National Publication No. H09-503424 that corresponds to U.S. Pat. No. 5,625,950 discloses an outer cutter(s) that is movable upward and downward and is tiltable in an arbitrary direction. In this prior art, a skin supporting rim (outer cutter ring) that surrounds the outer periphery of the outer cutter is provided, a projecting part that projects outwardly from the outer cutter is also provided in this skin supporting rim, and this projecting part turnably engages the engagement surface of the outer cutter holder (outer cutter housing). In other words, the skin supporting rim (outer cutter ring) that surrounds the outer cutter is provided so that it pivots with respect to both the outer cutter holder and the outer cutter. This skin supporting rim functions so that when the outer cutter is strongly pressed against the skin, it prevents the outer peripheral edge of the outer cutter from sinking deeply into the skin and shaving too deeply and damaging the skin.
Japanese Patent Application Laid-Open (Kokai) No. H02-213378 discloses an integrated cutter head and motor, and the cutter head and motor are provided so as to be pivotable in an arbitrary direction with respect to the shaver main body. The cutter head housing and the shaver main body are respectively formed as a spherical shell and a spherical cap type bearing shell, and both of these shells are provided so as to be slidable with respect to one another.
In Japanese Utility Model Application Laid-Open (Kokai) H06-31660, as in Japanese Patent Application Laid-Open (Kokai) No. H02-213378, an integrated cutter head and a motor which pivots with respect to the shaver main body is disclosed. However, Japanese Utility Model Application Laid-Open (Kokai) H06-31660 differs from Japanese Patent Application Laid-Open (Kokai) No. H02-213378 in that the head is joined to the shaver main body by four link elements, and the motor is pressed in the outer cutter direction by a conical coil.
In the shaver of Japanese Patent Application National Publication No. H09-503424 (or the U.S. Pat. No. 5,625,950), the outer circumference of the skin supporting rim that surrounds the outer periphery of the outer cutter turnably engages the outer cutter holder. As a result, it is unavoidable that the distance between the outer cutter and the outer cutter holder that surrounds the outer cutter becomes larger in the diameter direction. Therefore, the cutter unit comprising a single outer cutter and inner cutter and their ancillary components and the cutter head become large in size. Also, in a shaver that has a plurality of cutter units, there is a problem that the spacing between each cutter unit widens, and the feeling of use becomes poor.
Also, in the shaver of Japanese Patent Application National Publication No. H09-503424 (or the U.S. Pat. No. 5,625,950), the inner cutter(s) rotates about an axis (indicated by K, A, A1, A2) that is parallel to the top surface of the outer cutter and are passing through the center of the outer cutter(s). Therefore, particularly if the shaver is designed so that the inner cutter is supported so as to be rotated only about one axis, when the skin pressure is applied to this rotating axis, the skin supporting rim cannot turn, causing the problem that the shaving operation cannot be done smoothly. In addition, since the entire skin supporting rim does not move upward and downward (or is not sinkable), the improvement of the feeling of shaving is limited.
In the shavers of Japanese Patent Application Laid-Open (Kokai) No. H02-213378 and Japanese Utility Model Application Laid-Open (Kokai) H06-31660, the cutter head and motor are integrated, and the entirety of these pivots with respect to the shaver main body. As a result, the pivoting portion is large in size, and the shaver head is also large in size. In addition, the outer cutters in these prior art have no play in the vertical direction (rotational axis direction of the inner cutter); as a result, when the outer cutter presses the skin firmly, the outer cutter sinks deeply inside the skin and cuts deeply, and there is danger of skin damage. In particular, unlike Japanese Patent Application National Publication No. H09-503424 (or the U.S. Pat. No. 5,625,950), since a skin supporting rim is not provided, deep shaving can easily occur.